Help in assembling a very light mtb bike

warpath

im planning to assemble a very light mtb bike more or less 10kg if possible, hardtail I guess...but im not familiar with all the specs...can anyone give me a list or suggestion for the bike components with specs...thanks

toasty

It'd be easier starting with something like a Scott Scale, then switching the wheels, forks, tyres, seatpost/saddle and bars/stem.

Wheels are going to have to be <1500g or so which are going to be £400+, Rockshox Sids will probably do fork wise. Things like Maxxlite 310 tyres are what you see in light bike threads a lot, they're pretty much slicks but obviously save about a pound even over light sensible tyres.

http://www.evanscycles.com/products/scott/scale-10-2010-mountain-bike-ec020584

The old Scale used to be sub-22lbs, not sure if that one is though. Are you sure you want a 22lb mountain bike? They're not comfy or partcularly fun to ride in my opinion.

bomberesque

sub 10kg bike (with gears and front suspension) will cost you well north of a thousand pounds. You got the budget for that?

Aim around 12 and you can get some lovely deals and great vfm. if later you really want to get light and funky you'll know where to lose the weight.

google weight weenies if you what a view on where this obsession can lead. It is not for the faint of heart (or faint of wallet)

OTOH, a very light rigid singlespeed can be built much cheaper. but at what cost to riding comfort and flexibility? I love singlespeeds, but they're not for everyone and I wouldn't recommend it just to make the bike lighter.

Captain Turok

google weight weenies

+1

frogstomp

With a Boardman Pro HT you could probably get pretty close without too much effort.. 10.9kg to start with - lightweight pedals, bars and seatpost and you won't be far off.. good choice of wheels and fork and you could be under..

nicklouse

Captain Turok wrote:

google weight weenies

+1

http://weightweenies.starbike.com/artic ... ry=htbikes

bomberesque

that sub 6 kilo scale is mental

tri-sexual

sub 10 kg easy,
off the peg top of the range HT bikes from many major manufacturers will be around this sort of mark if not well below this weight especially cannondale flash and scott scale ltd (around 8kg mark).
you can even get FS bikes off the peg below the 10 kg mark ie scott spark ltd, the long travel "all mountain" scott ransom ltd is below 10.5 kg
the only limiting factor is your budget.
ultra light bikes are nice but require alot more TLC, rocky sections and serious drops where a heavier bike will tackle effortlessly will see you carrying your lightweight bike on your shoulder. heavier frames,wheels, tyres and components tend to handle alot more abuse and have longer lives than their lightweight counterparts.

toasty

frogstomp wrote:

With a Boardman Pro HT you could probably get pretty close without too much effort.. 10.9kg to start with - lightweight pedals, bars and seatpost and you won't be far off.. good choice of wheels and fork and you could be under..

The weight is most likely without pedals, the bars could lose about 130g max if you swap to a £100 carbon riser and I bet there's about the same again to be saved on the seatpost and saddle for a similar cost.

Assuming they're cheapish, but light 1800g-ish wheels, saving 200g-300g is going to cost about £300-£600 or so. Same again with the forks, 200g with a set of Sids instead of the Rebas for another £300-£600 or so depending on model.

The biggest catch with the Boardman over something like the Scott is you'll end up spending another £1k to get anywhere near than and you've already got a frame which is 1lb heavier holding you back.

I'd try riding a 10kg bike before setting your sights on it too rigidly. It's a completely different world from most mountain bikes you see, for me it's flexy wheels, narrow bars, almost road slick tyres, no fun at all. If you do buy something make sure to weigh it, claimed weights, especially on light bikes, are usually miles off.

toasty

tri-sexual wrote:

the long travel "all mountain" scott ransom ltd is below 10.5 kg

Are you sure that's not the Genius? Up until about 2008 the Ransom Ltd was nearer 14kg...

ride_whenever

10kg is a piece of piss, seriously, set yourself a challenge. My inbred was at 10.8 with massive 2.3" tyres and the front wheel off my jump bike, 700mm riser bars. And it's a steel frame :P

I'd say ignore every other bit of advice. Build it up from scratch using the on-one carbon frames that are coming out in the spring, sids, stans 355 on hope hubs with decent spokes, maybe dt revs, run sram xx, lightweight finishing kit and huge tyres run tubeless. That should just about come in under 10kg, and it wont ride like a sub 10kg bike.

tri-sexual

Toasty wrote:

tri-sexual wrote:

the long travel "all mountain" scott ransom ltd is below 10.5 kg

Are you sure that's not the Genius? Up until about 2008 the Ransom Ltd was nearer 14kg...

sorry, silly me, you are right- its the genius, the ransom ltd dont even exist anymore

toasty

ride_whenever wrote:

10kg is a piece of wee-wee, seriously, set yourself a challenge. My inbred was at 10.8 with massive 2.3" tyres and the front wheel off my jump bike, 700mm riser bars. And it's a steel frame :P

How did you weigh that?

My carbon Zaskar team with:

Full XT
Fox F100 forks (1650-1700g or so)
520g tyres run tubeless with 50g slime in each (fask trak lk)
1650g wheels (XT factory wheels)
I-Beam seatpost + Formula FX saddle (470g for both - 50g lighter than my 368mm Thomson Elite + Bel Air Ti)
Truvativ carbon team bars and team stem (165g + 130g)
Formula Oro K18s

All in, actually weighed on scales, weighed 24lbs (with 380g pedals). IE pretty much exactly the same as your On-One weighed?! Are you using claimed weights or something? Mine came to about 22lbs in claimed weights.

The top end Scales save about 1lb in the frame compared to my Zaskar, half a pound in the wheels another half a pound in forks etc. It's a very fine line to get that low.

ride_whenever

i don't have gears, i have huge quads instead.

toasty

Bah, cheating May as well use carbon rigid forks and save another wodge there too then :P

P-Jay

Silly light bikes make Jesus cry....

Get some Grrrr in your ride!

ride_whenever

no get a silly light bike that is as tough as old boots.

On the inbred I can just clatter through rough rocky sections, but i don't have to, if it so pleases me it's light enough that i can daintily skip down the sections from good ground to good ground expending what feels like no energy.

ride_whenever

actually the best bit is when your roadie friend picks it up to compare to his rat bike and it weighs less.

The Big Cheese

It's not that hard, my Marin comes in at 20lb, which is under 10kg obvisously, now although it's a very light frame, and with certain lightweight components, I kinda just bought various bits that I like aesthetically and put them on, I mean I don't race pro or anything, in fact, it gets used on the roads/light XC more than anything, but it came in nicve and light.

Start with ~3lb HT frame, light wheelset and light forks and you're nearly there....

toasty

ride_whenever wrote:

i don't have gears

ride_whenever wrote:

expending what feels like no energy.

These two sentences shouldn't go together imo, unless you go very slowly :P

BigJimmyB

tri-sexual wrote:

the long travel "all mountain" scott ransom ltd is below 10.5 kg

The 2010 Ransom 10 is 15kg

Posted before I read the entire thread

ride_whenever

Toasty wrote:

ride_whenever wrote:

i don't have gears

ride_whenever wrote:

expending what feels like no energy.

These two sentences shouldn't go together imo, unless you go very slowly :P

Nah, going slowly hurts like hell, going fast is the only way to roll on a singlespeed.

toasty

Well, up to a point, then your feet are spinning around in circles. Can't say I was that impressed with SS'ing :P

Tried it through last winter, hence the Stumpy in the sig, it got it's gears back shortly after. I'm sure it's great in places, I just couldn't find the line between hills being impossible and spinning too much, even on slight gradients. I think the difference is monstrous quad muscles, but you're still going to be limited at either end, for a 2lb saving?

ride_whenever

With 5/6 bikes i don't have time to look after gears on all my bikes! On the plus side i'm much better at spinning now!

toasty

3 bikes here (not counting the exploded one in the shed) and I don't have time to ride them at that! Dripping oil onto a cable once a month and turning a shifter barrel adjuster after a while on new bikes isn't eating into my time exactly :P

Keeping chains/bottom brackets/headsets grime and grit free is more effort in winter for me to be honest.

Salsa

As said 10kg is pretty easy to achieve with a HT, starting with a sub 1500g frame with carbon controls, decent wheels & XT level drive train should hit that weight. Mines at 8.25kg with no super exotic parts or silly slick tyres (I have Conti Race King UST @ 650g a tyre), but you really have to think about each part. It's taken me 4 years to go from 10kg when I first built it to what it's at now. With light weight bikes it's all in the details, I've just about given up on mine as the last few things I've changed have saved me only 10's of grams (KMCX10SL chain/Left X0 shifter with Avid Matchmaker etc) I will change the XT front mech but that's it, unless I find a deal on an XTR chainset that is.
Also very light bikes are not for everyone, they are obviously weaker (although they don't fall apart like some people think) but the main thing with mine is it's VERY responsive, even skittish & demands skill to ride but rewards input & although it's not for everyone it suits my riding style.

El Capitano

Salsa wrote:

Also very light bikes are not for everyone, they are obviously weaker.

This.

I got my XTC down to about 9 kg, before everything started breaking! And I didn't go for stupidly light carbon bars/stem/seatpost either. There are good places to lose weight and there are places where a bit of weight is necessary - tyres for example - Maxxix Flyweights are nice and light at 330g each, but puncture really easily on the road, never mind doing as extreme as a fire-road. Similarly, there are some nice light grips on Poshbike's site - 8g each. Nice, but not exactly very grippy. I've also done the Fibrelite cage plate on an XTR rear mech - it shattered when I stacked at Bristol Bike-Fest. Again, I also have a pair of RS SID's, Circa 2002 - weight 1189g. Again, very light, but they don't exactly work very well...

Also, don't just look at the weight of the component to get the lightest possible, look at compatibility as well. I have a USE Alien Seatpost, which is stupidly light at 159g. However, due to the way the seat clamp works on the saddle rails, I can't use it with a saddle with hollow Ti rails. So I now use a light saddle and heavier seatpost...

Ti and alloy bolts are another way of losing some weight (and a lot of money). It's a personal favourite of mine, but with a complete bike weight saving of around 100g for £stupid, it is only for the really obssesive weight-weenie

My NRS (which is what the XTC has evolved to now) weights about 24lbs now, different components that actually work for enduro events, rather than something that's light that had reliability issues.

Oh and another word of warning, getting your bike as light as possible becomes obssesive. Very obssesive. And expensive...